Spain's actions "shouldn't be allowed by the European Union as it would be incompatible with the commitments assumed by the bloc in international trade agreements and the rules stipulated by the WTO," Argentina's Foreign Ministry said in a letter to EC trade director Jean-Luc Demarty.

Spain retaliated against Argentina in April for the expropriation of YPF, with a measure to curtail Argentine biodiesel imports.

Spain started requiring that all biodiesel used there be sourced from EU producers. The measure effectively blocks imports of the fuel from Argentina, which is the main supplier to Spain's biodiesel market.

Argentine President Cristina Fernandez de Kirchner sent a bill to the Senate in April, under which the government would obtain a 51% stake in YPF, effectively expropriating the company amid escalating tensions and accusations of continued decline in oil and gas production in the country.

Spain threatened consequences for Argentina in response to the expropriation of YPF from Madrid-listed Repsol.